Integrated circuits (IC) may be used in a wide range of designs and products, some integrated circuits may include an Non Volatile Memory (NVM) array. An NVM array may be composed of NVM cells, ancillary circuitry, a controller and additional circuits. The ancillary circuitry may include for example: array controls, address decoding circuits and sense amplifiers (SA) configured to determine a value/level of one or more targeted NVM cell.
Some NVM memory array types may include: floating gate arrays, array of eCT cells, array of MirrorBit cells, charge trapping cells and more.
The NVM cells may be single bit or multi-level storage cells (MLC) and the cells may be programmable to different states, for example in a single bit configuration the cell may be programmable to either an erased (ERS) or programmed (PRG) stage.
According to some embodiments, the NVM cells may be accessed through wordlines (WLs), bitlines (BLs), select lines (SLs) or otherwise. For each operational mode (Programming of cells, Erasing of cells, Reading of cells etc.) the WLs BLs and/or SLs may be activated accordingly. Which WL, which BL and which SL to operate, as well as if to operate them at all and what voltage to supply to them is dependent on the mode algorithm (read algorithm, program algorithm, read algorithm and so on) and the selected addresses, the specific technology being used and more. Some arrays may not include SLs or WLs or otherwise.
Comparators may be utilized in ICs to compare two signals and output a result indicating which of the two signals is greater than the other. Comparators may be used for logic functionality, analog circuits and more.
A sense amplifier (SA), which may also be considered a comparator, may be utilized in conjunction with a memory array to determine a stored value of an NVM cell. A first input to a sense amplifier may be a current/voltage associated with a targeted NVM cell within the array received through a bitline. A second input to a sense amplifier may be a current/voltage associated with a reference cell which in some configurations may be received through a bitline. The SA may compare the two inputs and determine if the targeted cell is in a PGM or ERS state (or otherwise for MLC).
According to some embodiments, a SA may receive and sample an input. In sampled configurations developing/integrated input voltages cannot be compared/accessed. Furthermore, these types of configurations may include passgates on the input line (connected to the BL) to enable the sampling. A passgate on the input line may add noise to the input signal.
Some transistor types which may be used in associated circuitry are Pmos, Nmos, low voltage (lv) Nmos, lv Pmos, high voltage (HV) Nmos and HV Pmos, Zmos, BJT and more. HV transistors/cells may be differentiated from LV transistors/cells by being designed/configured to enable operation in a higher range of voltages across their channel compared to LV cells (for example, between a drain node and a source node of the transistor) and/or across the gate (for example: between their gate and bulk or ground node) and may include a thick oxide region compared to LV devices.
Furthermore, some circuits may use one or more switches for controlling different modes of operation, enabling connection between two points or disconnecting to points of an electrical connection and/or disabling of current from going through the points. Some switches may include, a single Pmos transistor, a signal Nmos transistor, a pass gate or CMOS switch (which may include both Nmos and Pmos transistors). For convention and clarity for the purpose of this description it will be understood that when (s) a switch is described as on or closed it means that two ports of the switch are connected and current may be enabled to run through and (b) a switch is described as off or open it means that two ports of the switch are disconnected and current is not enabled to flow through the ports. A switch may be operated, for example by applying a predetermined voltage to a gate node of at least one transistor included in the switch.
In ICs some global/general supplies may be provided such as ground voltage (GND) which may be zero, VDD which may be a medium voltage used for typical logical circuits, VDDH may also be selectively used to supply a higher voltage. Additional operational voltages may be supply voltages for operating memories or circuits requiring higher voltages (in absolute values) which may be termed supply1, supply1 and the like.